Loud-speaker



Feb. 25, 1930. M. v. OSBORNE LOUD SPEAKER Fig d April 6, 1927 PatentedFeb. 25, 1930 MARK V. OSBORNE, OF MASSILLON, OHIO LOUD-SPEAKERApplication filed April 6, 1927.

My inventionrelates to loud speakers for amplifying sounds deliveredthereto as by the reproducing unit of a radio or thelike and the objectsof my invention are to provide a compact, easily and economicallymanufactured loud speaker which will amplify sounds very efliciently andthrough a relatively large range of wave lengths.

These objects are attained by a construction and arrangement hereinafterset forth in detail and which may be stated in general terms asincluding a sound delivery horn communicatinginto but not contactingwith one cup shaped deflecting chamber having an open end and whoseinner surface preferably conforms to a surface of revolution, and thecup shaped deflecting chamber communicating into but not contacting withan annular deflecting chamber having an open end and an inner surfacepreferably conforming to a surface of revolution and the annulardeflect- I ing chamber similarly communicating with one or more similarannular deflecting chambers.

A preferred embodiment of the invention is illustrated in theaccompanying drawing forming part hereof, in which Figure 1 is a partfront elevation and part sectional view of the improved loud speaker ason line 11, Fig. 2; and

Fig. 2, an axial sectional view thereof as on line 22, Fig. 1.

Similar numerals refer to similar parts throughout the drawing.

The improved loud speaker indicated generally at 10 includes preferablyin the form of an integral casting or the like, an outer shell 11including preferably concentric and tapered tubular walls 11 11 and 11,the intermediate wall 11 being spaced from and encircling the inner wall11, and being itself spaced from and encircled by the outer wall 11, andthere being a common end closure 11 between one end of the walls 11, 11and 11.

The inner surfaces of the shell 11 preferably conform to surfaces ofrevolution about the longitudinal axis XX, and the inner surface 12 ofthe wall 11 forms a central tapered horn 13 preferably having a smallerouter end 60 14 for sound receiving connection with a Serial No.181,446.

source of sound as the sound reproducing unit 15 of a radio or the like,indicated in dotted lines in Fig. 2.

The outer surface 16 of the wall 11 together with the inner surface 17of the wall 11 and the preferably curved inner surface 18 of the endclosure 11 form an annular defleeting chamber 19 about the horn 13, theannular deflecting chamber 19 having an open end 20 adjacent the openlarger end 21 of the horn.

Another open ended annular deflecting chamber 22 is formed in the shell11 about the chamber 19 by the outer surface 23 of the wall 11, theinner surface 24 of the wall 11, and the preferably curved inner surface25 of the end closure 11.

The open end of the wall 11 preferably extends longitudinally beyond theopen ends of the wall 11, and preferably terminates in a curved flare26.

In addition to the outer shell 11, the loud speaker includes also aninner shell 27 preferably in the form of an integral casting or thelike, and including preferably concentric and tapered tubular walls 27and 27, the inner wall 27 being spaced from and encircled by the outerwall 27', and there being a common end closure 27 for one end of thewalls 27 and 27 The inner surfaces of the shell 27 preferably conform tosurfaces of revolution about the longitudinal axis XX and the innersurface 28 of the wall 27 together with the preferably curved innersurface 29 of the end closure 27, having a central apex 30 outwardlyextending therefrom, form a cup shaped deflecting chamber 31 in theshell 27, and the chamber 31 has an open end 32.

An open ended annular deflecting chamber 33 is also formed in the shell27 about the cup shaped deflecting chamber 31 by the outer surface 34 ofthe wall 27*, the inner surface 35 of the wall 27*, and the preferablycurved inner deflecting surface 36 of the end closure 27 The open end 37of the annular chamber 33 is preferably spaced slightly back of the openend 32 of the cup chamber 31; and the outer surface of the end closure27 d is preferably in the form of a tapered cone 38.

The shell 27 is preferably arranged within the shell 11 so that theshells are coaxial, and the open ends of the shell 27 extend in theopposite direction to, and fit over the open ends of the inner walls 11and 11 of the shell 11, and means are provided which may be sleeves 39and 39 for laterally spacing the shells from each other, and screws 40and 40 may be passed through the wall 11, and the sleeves 39 and 39, andscrewed into the wall 27 for securing the shells to each other, and thewall 11 is preferably provided with longitudinally extending slots 41through which the screws extend for providing longitudinal adjustment ofthe shells with reference to each other.

The sound delivering horn 13 thus communicates into but does not contactwith the cup shaped deflecting chamber 31 which itself communicates withbut does not contact with the annular deflecting chamber 19, and thechamber 19 communicates with but not contact with the annular deflectingchamber 33 which finally communicates with but does not contact with theannular deflecting chamber 22.

In other words as best illustrated in Fig. 2, the arrangement of theshells 11 and 27 provides for transmitting sound waves and the like, aplurality of reversely directed annular ring passageways communicatingwith each other and having curved sound deflecting surfaces at thecommunicating, openings.

By reason of the fact that the tubular walls are tapered as illustrated,a sound wave entering the loud speaker through its horn 13 will travelsubstantially the total ;,longitudinal distance which it would travel ifthe loud speaker were in the form of a straight tapered horn having atotal length equal to the total length of all of the straight taperedsections of the two shells, and such a straight horn would in itselfprovide a certain amplification for the sounds entering therein.

In addition to this horn effect, the improved loud speaker is providedwith the deflectin efiect on the sound waves of the severa curveddeflecting surfaces 29, 18, 36 and 25, successively, which tend tosmooth out, for example, musical sounds which may enter the horn 13 andto eliminate to a certain extent undesirable sounds intermingledtherewith.

The shell 11 may be provided with suitable feet 42 for supporting theloud speaker on a table or the like.

The arrangement of the solid common end closure 11 for the outer shell11, and of the conical solid end closure 27 d of the inner shell 27prevents vibration therein which otherwise might be set up by the soundwaves being deflected by the curved inner surfaces thereof.

Moreover the outer conical form of the end closure 27 of the inner shell27 has been found to deliver the ring-like sound waves issuing from theloud speaker more smoothly than when the outer surface of the endclosure is made flat.

I claim:

A loud speaker including an outer shell having walls forming a horn anda deflecting chamber, an inner shell having walls forming a deflectingchamber for receiving sound waves from the outer shell, and means forradially spacing the shells from each other and for adjusting thelongitudinal axial distance between the shells.

In testimony that I claim the above, I have hereunto subscribed m name.

MA K V. OSBORNE.

